I see. In my experience so far, MVC provides a good enough separation of concerns and in the absence of an immediate need for an API, it is more economical to

I see. In my experience so far, MVC provides a good enough separation of concerns and in the absence of an immediate need for an API, it is more economical to build a monolithic app. Avoiding building a second application for the front end offers huge savings. Adding an API is fairly easy (Rails) and Turbolinks offer a great middle ground for native apps.